... valve 1.19years experience 2.low leakagerate,high quality 3.OEM is welcome 4.CE High quality Anti-sweat worm gear butterfly valve Model ... medium Air, water, sewage, steam, gas, oil, etc. Drive type Manual, worm worm gear drive, gas drive, electric drive. Part name ... bad working condition. 7.Center plate structure, small torque of open and close. 8.Long service life. Standing the test of ...